Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Many users use earphones for listening to music or watching videos. Mobile communication devices are often equipped with a call function unlike multimedia players. During a call, incoming audio may be output through earphones. Inconveniently, outgoing audio may be transmitted during the call using a separate microphone built into the mobile communication device.